Accused killer Seth Mazzaglia, right, is escorted off the elevator as he arrives at the Strafford County Superior Court Wednesday, June 25, 2014 in Dover, N.H. Mazzaglia is accused of killing Elizabeth "Lizzi" Marriott in Oct. 2012 after she refused his sexual advances. (AP Photo/Jim Cole)

DOVER, N.H. (AP) — The man convicted of raping and killing a University of New Hampshire student in October 2012 will be sentenced in August.

Prosecutors said Wednesday they also intend to prosecute Seth Mazzaglia of Dover, 31, on a charge that he enlisted a cellmate to help plot his escape.

Prosecutor Peter Hinckley told WMUR that he does not consider it a waste of resources to pursue the charge of criminal solicitation, "because he committed the crime."

Mazzaglia was convicted June 27 of first-degree murder and other felonies in the death of 19-year-old Elizabeth "Lizzi" Marriott of Westborough, Massachusetts. Prosecutors say he strangled, then raped Marriott in his Dover apartment after she rebuffed his sexual advances.

Jurors heard testimony over the course of 19 days and convicted Mazzaglia after a full day of deliberations.

The key witness, 20-year-old Kathryn McDonough, was Mazzaglia's girlfriend when she lured Marriott to their apartment. She testified that Mazzaglia wanted another woman to join their sexual escapades, which included bondage and discipline.

McDonough first told investigators that Marriott died during rough sex between the two women that involved restraints. After getting immunity from prosecution, McDonough changed her story and said Mazzaglia strangled Marriott, then raped her.

The trial hinged on McDonough's credibility. Mazzaglia did not testify.

"I think Mr. Mazzaglia had control over her and she was afraid of him.," said Clifford, 52. "We just thought, 'She's on the witness stand now and she doesn't have anything left to lose,' and she came to the realization that, 'I need to do the right thing.'"

McDonough pleaded guilty to hindering the prosecution, conspiracy and witness tampering. She is serving 1-1/2 to 3 years.

Mazzaglia faces life in prison without possibility of parole when he's sentenced Aug. 14.

His trial on the criminal solicitation charge is scheduled for Nov. 3.